Organosilicon compounds having a hydrolyzable silyl group and an organic reactive group are generally known as “silane coupling agents” and often used as adhesives, paint additives and resin modifiers, for example, since they are capable of forming bonds between inorganic materials and organic materials.
Typical of the organic reactive group are vinyl, amino. epoxy, (meth)acrylic, mercapto, isocyanate, ketimine structure, and styryl groups. Silane coupling agents having such groups are well known and used in a variety of applications.
As the requirements on physical properties become severer in many applications, the organic material or resin used therein makes a transition from general-purpose materials to special materials like super-engineering plastics. The silane coupling agent capable of improving adhesion to such special materials is not necessarily limited to those having the above functional groups. There is a need for a silane coupling agent having a functional group compatible with an individual resin material.
Included in the silane coupling agent suited for use with highly polar, heat-resistant organic materials such as polyimides and polyamides are silane coupling agents having acid anhydride or amic acid structure in monomer constituent units and imide ring-containing silane coupling agents of similar structure. They are used as an adhesion promoter for resist materials as reported in the literature.
Patent Documents 1 to 4 disclose resist materials comprising silane coupling agents having an imide structure group. These proposals rely on the adhesion promoting effect due to the compatibility and interaction of the imide structure. Since the imide structure itself has no chemical bonding ability, there is still left room for improvement in the desired adhesion.
Also Patent Documents 5 to 7 disclose silane coupling agents having an amic acid structure group and resist materials comprising the silanes. All these documents relate to only silane coupling agent monomers obtained from reaction of an acid anhydride ring-containing silane coupling agent with a primary amine compound, but nowhere refer to high molecular weight products obtained by heating the amic acids. The adhesion promoting effect of these techniques is still insufficient.